The leading corrections to general relativity can be parametrized by higher-derivative interactions in a low-energy effective field theory, in a way that is general and agnostic to the precise UV completion of gravity. Using numerical methods, we compute the leading-order corrections to the Kerr metric across the entire range of subextremal values of spin and analyze their impact on physical quantities. We find that rapidly rotating black holes are most affected by the higher-derivative corrections, making them especially sensitive probes of new physics. A dataset of solutions and the code used to produce them are publicly available.